The present invention relates to a neck and head protection device for use by drivers of vehicles subject to high deceleration or crash forces.
FIG. 1 schematically represents a five-point seat belt system 20 having two shoulder belts 22a and 22b, two lap belts 24a and 24b and a crotch belt or strap 26. A latching mechanism(s) 30 comprises at least one buckle 32 and a plurality of tongues 34a, 34b. The arrangement of the seat belt, tongues and buckle is designed to permit a quick release and permit the driver to easily exit the vehicle.
When a high-performance vehicle such as a race car is in an accident or otherwise decelerates, the vehicle is subjected to extremely high g forces. Additionally, if the driver""s head is not restrained, these forces are amplified dramatically as the head, increased in mass by even a modestly sized helmet, moves uncontrollably.
Various solutions have been proposed to limit or otherwise control the motion of the head and neck of the driver. U.S. Pat. No. 4,638,510 proposes the use of a yoke held in place by the downward forces of the shoulder belt (on the driver""s shoulders). Various tethers are anchored to a rear portion of the yoke and extend to connection points on the helmet. These connection points are preferably located in a plane that includes the head-helmet center of gravity. One deficiency of this type of system is the side-to-side rotary motion of the driver""s head, during normal driving situations, is significantly limited. Another deficiency of this type of system is its difficult removal in an emergency and restriction of driver egress from a damaged vehicle.
FIGS. 2 and 3 illustrate an alternate, prior art proposal in which the helmet restraint system comprises a bar 400, which rests on the occupant""s back, and is received under each of the respective shoulder belts 22a and 22b and held in place by the belts. A plurality of tethers or straps 402 and 404 extend laterally across the rear of the helmet and are connected to a center strap or tether 406. End 408a of tether 406 is looped about the centers of both tethers/straps 402 and 404. The other end 408b of tether or strap 406 is looped about the bar 400. As can be seen in both FIGS. 2 and 3, the tethers 402-406 are all situated substantially below the effective center of gravity of the head-helmet. Consequently during an accident, the device fails to limit forward motion of the head relative to the restrained torso, thereby leading to large neck flexion moments and tensile forces. In addition, it has been proposed that at least one of the tethers such as tether 406 be made of a yieldable material to lessen the impact force on the driver""s head.
It is an object of the present invention to provide an improvement to crash safety.
It is a further object of the present invention to provide a helmet restraint system that reduces spine and neck injuries while not restricting occupant egress from a crashed or damaged vehicle.
Accordingly the invention comprises: an occupant helmet protection system usable with an occupant helmet and a seat belt system, the seat belt system of the type including at least a first and a second shoulder belt, each of which when worn is positioned to lie across a respective shoulder of an occupant, the helmet occupant protection system comprising: an energy absorbing, flexible tether having a first end operatively connected to the helmet in alignment with an effective center of gravity of the combined helmet and occupant""s head, the tether including a second end connected to a tether anchor point; a frame member loosely supported about the shoulders of the occupant and including a center or tower portion, the center or tower portion having a tether guide means for changing the direction of the tether and to provide a low friction surface for the tether, the tether guide means located in alignment with or slightly above a horizontal first plane, which passes through the effective center of gravity of the head-helmet combination and the tether-helmet anchor point, the tether passing about and not connected to the frame member.